class Solution {
    public int search(int[] nums, int target) {
        int left = 0;
        int right = nums.length-1;
        while (left <= right) {
            int mid = left+(right-left)/2;
            if(nums[mid] < target) {
                left = mid+1;
            } else if (nums[mid] > target) {
                right = mid-1;
            }else {
                return mid;
            }
        }
        return -1;
    }
}
/*
class Solution1 {
    public int search(int[] nums, int target) {

        //朴素二分模版
        while (left <= right) {
            int mid = left + (right - left) / 2;//避免数据溢出
            //int mid = left + (right - left + 1) / 2;在朴素二分中，加不加1均可
            if(....) {
                left = mid+1;
            } else if (....) {
                right = mid-1;
            }else {
                return ....;
            }
        }
        return -1;
    }
}*/
